DESCRIPTION: STDs and HIV reduce fertility and increase pregnancy loss. Sub-fertility may lead to marital instability and dissolution, resulting in increased high risk sexual behaviors and thus enhanced M/MV risk. HIV testing also places stress on marriages. We propose to use a unique data set from a community-based study in rural Rakai District, Uganda. Data are available for 11,315 women and 10,698 men who provided detailed socio-demographic, health and behavioral information, and samples for STD diagnosis, at 5 home visits conducted at 10-month intervals (40 months follow up). These panel data will be used to address the following specific aims using an instrumental variable approach and fixed-effects models to control for endogeneity and unobserved heterogeneity. 1) Among women at risk of conception, we will estimate the effects of HIV and other STDs on pregnancy and pregnancy loss rates in HIV+ and HIV- women, with or without other STDS, after adjustment for covariates such as age, marital status, sub-fertility, frequency of intercourse, contraception and knowledge of HIV status. 2) Longitudinal analyses will be used to assess the effects of prevalent HIV/STD infections, reduced fertility and HIV testing/counseling on family planning use (condom /other modem methods) and rates of marital dissolution, subsequent sexual behaviors and STD/HIV acquisition. Data on couples and sexual networks will also be considered. 3) Reduced fertility of HIV+ women causes bias in antenatal surveillance of HIV, leading to underestimation of population HIV prevalence and artifacts in HIV trends. We will estimate the magnitude of this bias in HIV prevalence estimates among pregnant women relative to the population of reproductive age, and assess how such bias varies by age, parity, duration of marriage, and over time. Demographic projections of the impact of the HIV epidemic are largely based on antenatal HIV seroprevalence estimates and fail to account for the fertility inhibiting effects of HIV. In collaboration with the U.S. Bureau of Census, data from the proposed study will be used to revise demographic projections of the effects of HIV on population growth, composition and AIDS orphanhood.